To avoid problems with misusage of mailing lists, I have decided to set up a separate server, and put mailman on it (homepage or here).
Why a separate server? Wel the production server is in max usage with over 1000 users on it, so no touching 😉 Also I wanted to try out the configuration the virtual platform.
As OS CentOS 6 (64-bitni), who has its own mailman package 2.1.12-18.
What do I turn off at the start, so that I have no problems later on :
SE Linux
ip6tables

Nice link is here and here.
Main configuration file is /etc/httpd/conf.d/mailman.conf.
After every change restart Apache service.